Automotive drive system

ABSTRACT

An internal combustion engine is connected to a fixed displacement pump normally having its inlet connected to a reservoir and its outlet connected to an accumulator. To start the engine, selectively operable valves connect the inlet of the pump to the accumulator and the outlet to the reservoir to drive the pump as a motor to rotate the engine. Also, a fixed displacement motor has an inlet connected by a forward solenoid valve to the accumulator and pump and connected by a brake solenoid valve to the reservoir. The motor also has an outlet connected to the pump and the accumulator by a reverse solenoid valve and connected to the reservoir by a neutral solenoid valve.

This is a continuation of application Ser. No. 765,951 filed Feb. 7,1977 now abandoned.

DESCRIPTION

This invention relates to an improved automotive drive system and hasfor an object thereof the provision of a new and improved automotivedrive system.

Another object of the invention is to provide an automotive drive systemincluding an internal combustion engine, a pump connected mechanicallyto the engine and an accumulator normally supplied with liquid underpressure from the pump and adapted to be selectively connected to theinlet of the pump to drive the pump as a motor to start the engine.

A further object of the invention is to provide an automotive drivesystem including an accumulator, a pump normally driven by an internalcombustion engine and adapted to be driven as a motor to start theengine, and a motor adapted to be selectively driven in forward orreverse by the accumulator and the pump, to be driven by wheels to actas a pump and to be connected in a neutral condition to a reservoir.

Another object of the invention is to provide an automotive drive systemincluding a source of hydraulic liquid under pressure and a fixeddisplacement motor adapted to be selectively connected to the source anda reservoir in forward, reverse, braking or neutral.

In the drawings:

FIG. 1 is a schematic view of an improved automotive drive systemforming one embodiment of the invention with a drive pump thereof beingused as a starter motor and a drive motor in a neutral condition;

FIG. 2 is a schematic view of the automotive drive system of FIG. 1 in aforward drive condition and drive pump connected as a pump;

FIG. 3 is a schematic view of the automotive drive system of FIG. 1 in areverse drive condition and drive pump connected as a pump;

FIG. 4 is a schematic view of the automotive drive system of FIG. 1 in abraking condition and drive pump connected as a pump.

An improved automotive drive system forming one specific embodiment ofthe invention includes a prime mover in the form of an internalcombustion engine 10, the speed of which is set to operate at its mostefficient engine speed. Usually, this is slightly over one-half themaximum rated RPM. When the vehicle speed reaches approximately one-halfthe maximum speed of the vehicle, or extra rapid acceleration is needed,the engine 10 will operate at a higher speed. Such speed will bedetermined by the position of a foot throttle (not shown). The enginehas a drive shaft 12 mechanically connected to a fixed displacementhydraulic pump 14 which also can operate as a fixed displacementhydraulic motor. The engine has an ignition circuit 16 activated when akey operated switch 18 and contacts 20 of a pressure responsive switch22 are closed to connect it to a battery 24. Contacts 26 of the switch22 are connected in series with normally closed contacts 28 which areopened, when the engine reaches a minimum operating speed, by a knownspeed responsive device 30 driven by the engine.

The fixed displacement pump 14 also serves as a fixed displacement motorto rotate the engine 10 to start the engine. To start the engine,switches 18, 82 and 120 are closed by the driver, the system being inits neutral condition as is shown in FIG. 1. The contacts 28 are closedsince the engine is not running so that solenoids 34 and 35 areenergized to open valves 36 and 37. It is assumed that pressure onhydraulic liquid 38 in an accumulator 40 is lower than the desiredminimum operating pressure of, for example, 1700 pounds per square inch.The switch 22 is set to energize whenever the pressure drops below apredetermined level, for example, 2,000 PSI, whereby contacts 26 closeand current flows through closed contacts 28 and opens valves 36 and 37by energizing solenoids 34 and 35. The liquid flows from the accumulator40 through lines 42, 44, 46, 48 and 50, the valve 36 and lines 52 and 54to port 56 of the pump 14, through the pump 14 (to drive it as a motor),out port 58 of the pump, through lines 60 and 62 of the valve 37 andlines 64, 66, 68 and 70 to a reservoir 72. This drives the pump as amotor to turn the engine to start it. When it has started and reached alow level operating speed, the speed responsive device opens the switch28. Opening of the switch 28 drops out the solenoids 34 and 35 and thevalves 36 and 37 close. The pump 14 now acts as a pump to pump theliquid from the line 54 through lines 60 and 74, a check valve 76 andline 78 to the line 48. A fixed displacement hydraulic motor 100, whichserves as the vehicle drive motor and also may operate as a pump, may ormay not be turning depending on whether or not the vehicle is in motionwhen the engine start cycle occurs. If we assume that the vehicle ismoving forward, and motor 100 rotating and valves 128 and 90 are bothopen, the motor will be in a neutral condition and oil from reservoir 72will flow through valve 128, motor 100 and valve 90 back to thereservoir 72.

Motor 100 has two ports 98 and 102, respectively referred to as theinlet and outlet ports. The inlet port 98 of the motor 100 is connectedby a "forward" solenoid valve 88 to the accumulator 40 and by a "brake"solenoid valve 128 to the reservoir 72. The outlet port 102 of the motor100 is connected by a "reverse" solenoid valve 130 to the accumulatorand by a "neutral" solenoid valve 90 to the reservoir.

To drive the automobile forward, the driver closes switch 80 preferablyplacing the system in the condition shown in FIG. 2, and opens switch120. Closing the switch 80 causes energization of solenoid 84. Openingswitch 120 de-energizes solenoid 124. Thus, valve 88 opens and valve 128closes. The liquid 38 then is forced from the line 42 or 46 through line92, the valve 88, lines 94 and 96; port 98 of motor 100; the motor 100;port 102 of the motor 100; lines 104 and 106; the valve 90, and line 108to the line 66 leading to the pump through a line 107, a check valve 109and lines 111 and 54 if the engine is running. If the engine is notrunning, the oil will flow through line 68 to the reservoir 72. Themotor is connected to drive axle 110 and drives drive wheels 112 of theautomobile in a forward direction.

To drive the automobile in reverse, the driver places the system in thecondition thereon shown in FIG. 3 by actuating a switch in the drivingcompartment and depressing the accelerator. The switches 80 and 82 areopen and switches 120 and 122 are closed to energize solenoid windings124 and 126 to open valves 128 and 130. The liquid 38 pumped from thepump 14 or flow from accumulator 40, then flows from the line 46 throughline 140, the valve 130, lines 142 and 104, the motor 100, lines 96 and144, the valve 128 and line 146.

To brake the automobile, the system is placed by the driver in thecondition shown in FIG. 4, by removing his foot from the accelerator.The switch 120 is closed to cause the valve 128 to open. The motor 100then acts as a pump to pump the liquid 38 from the line 146 through thevalve 128, lines 144 and 96; the motor 100; lines 104 and 150; checkvalve 152 and lines 154, 44 and 42 to the accumulator 40.

To start the engine 10 under a condition in which there is insufficientpressure in the accumulator 40 to start the engine, the driver closesthe switch 18 to open the valves 36 and 37 and closes the switch 120.The automobile then is pushed, or coasted downhill, and the motor 100 isin its pumping phase (braking) and pumps the liquid 38 through the valve152 to the accumulator and the pump 14, which is thereby driven as amotor to turn over the engine and start it. Also, a handpump (not shown)could be used to pump oil from the reservoir into the accumulator.

An adjustable relief valve 160 is provided to prevent the pressure inthe accumulator from exceeding a predetermined maximum, for example,3,200 pounds per square inch. The pressure switch 22 is set to be closedto start the engine 10 whenever the pressure is less than a desiredpredetermined minimum, for example, 1,700 pounds per square inch. Theswitch 22 is set to open the contacts 20 and 26 at the upper limit ofthe desired operating ranges, for example, 2,800 pounds per square inch.The motor 100 then is driven by the accumulator 40 alone, without theengine 10, until the pressure goes below a lower limit of, for example1,700 pounds per square inch, the switch 22 then closing the contacts 20and 26.

For starting, using the pump as a starter motor, the the engine 10 isturned over very rapidly as the starter motor is capable of providing asmuch horsepower as the engine. This rapid starting of the engineeliminates pollutants during the frequent stop/start cycle of theengine.

What is claimed is:
 1. In a wheeled vehicle having an engine for drivingthe vehicle, a starting system for selectively storing energy normallylost in braking the vehicle and releasing the stored energy to start theengine, said starting system comprising:(a) an accumulator for storingpressurized fluid; (b) a reservoir for storing fluid; (c) hydraulic pumpmeans mechanically coupled to the wheels of said vehicle for beingdriven by said wheels, said pump means having an inlet and an outlet;(d) first control means for selectively hydraulically connecting theinlet of said pump means to said reservoir and the outlet of said pumpmeans to said accumulator for pumping hydraulic fluid from saidreservoir into said accumulator for storage therein under pressure inresponse to the driving of said pump means by said wheels to brake saidvehicle; (e) hydraulic motor means mechanically coupled to said enginefor driving and thereby starting said engine, said motor means having aninlet and an outlet; (f) second control means for selectivelyhydraulically connecting the inlet of said motor means to saidaccumulator for receiving said hydraulic fluid from said accumulator andthe outlet of said motor means to said reservoir to drive said enginefor starting; and (g) speed responsive means connected to said enginefor determining the speed of rotation thereof, said second control meansincluding valve means responsive to said speed responsive means forstopping the flow of hydraulic fluid from said accumulator to said motormeans when the engine has reached a predetermined speed.
 2. In a wheeledvehicle having an engine for driving the vehicle, a starting system forselectively storing energy normally lost in braking the vehicle andreleasing the stored energy to start the engine, said starting systemcomprising:(a) an accumulator for storing pressurized fluid; (b) areservoir for storing fluid; (c) hydraulic pump means mechanicallycoupled to the wheels of said vehicle for being driven by said wheels,said pump means having an inlet and an outlet; (d) first control meansfor selectively hydraulically connecting the inlet of said pump means tosaid reservoir and the outlet of said pump means to said accumulator forpumping hydraulic fluid from said reservoir into said accumulator forstorage therein under pressure in response to the driving of said pumpmeans by said wheels to brake said vehicle; (e) hydraulic motor meansmechanically coupled to said engine for driving and thereby startingsaid engine, said motor means having an inlet and an outlet; (f) secondcontrol means for selectively hydraulically connecting the inlet of saidmotor means to said accumulator for receiving said hydraulic fluid fromsaid accumulator and the outlet of said motor means to said reservoir todrive said engine for starting; and (g) pressure responsive means,connected to said accumulator and to said second control means, forpreventing the flow of hydraulic fluid from said accumulator to saidmotor means if the pressure in said accumulator exceeds a predeterminedmaximum.
 3. The starting system of claim 2 wherein said engine includesan ignition system and said pressure responsive means includes means fordisabling said ignition system if the pressure in said accumulatorexceeds said predetermined maximum.
 4. In a wheeled vehicle having anengine for driving the vehicle, a starting system for selectivelystoring energy normally lost in braking the vehicle and releasing thestored energy to start the engine, said starting system comprising:(a)an accumulator for storing pressurized fluid; (b) a reservoir forstoring fluid; (c) hydraulic pump means mechanically coupled to thewheels of said vehicle for being driven by said wheels, said pump meanshaving an inlet and an outlet; (d) first control means for selectivelyhydraulically connecting the inlet of said pump means to said reservoirand the outlet of said pump means to said accumulator for pumpinghydraulic fluid from said reservoir into said accumulator for storagetherein under pressure in response to the driving of said pump means bysaid wheels to brake said vehicle; (e) hydraulic motor meansmechanically coupled to said engine for driving and thereby startingsaid engine, said motor means having an inlet and an outlet; (f) secondcontrol means for selectively hydraulically connecting the inlet of saidmotor means to said accumulator for receiving said hydraulic fluid fromsaid accumulator and the outlet of said motor means to said reservoir todrive said engine for starting; and (g) pressure responsive means,connected to said accumulator and to said second control means, fordirecting the flow of hydraulic fluid from said accumulator to saidmotor means in response to a drop in the pressure in said accumulatorbelow a predetermined minimum.
 5. The starting system of claim 4 whereinsaid engine includes an ignition system and said pressure responsivemeans includes means for turning on said ignition system if the pressurein said accumulator is below said predetermined minimum.
 6. In a wheeledvehicle having an engine for driving the vehicle, a starting system forselectively storing energy normally lost in braking the vehicle andreleasing the stored energy to start the engine, said starting systemcomprising:(a) an accumulator for storing pressurized fluid; (b) areservoir for storing fluid; (c) hydraulic pump means mechanicallycoupled to the wheels of said vehicle for being driven by said wheels,said pump means having an inlet and an outlet; (d) first control meansfor selectively hydraulically connecting the inlet of said pump means tosaid reservoir and the outlet of said pump means to said accumulator forpumping hydraulic fluid from said reservoir into said accumulator forstorage therein under pressure in response to the driving of said pumpmeans by said wheels to brake said vehicle; (e) hydraulic motor-pumpmeans mechanically coupled to said engine for selectively either drivingand thereby starting said engine or being driven by said engine to pumpfluid, said motor-pump means having an inlet and an outlet; (f) firstvalve means connected to the inlet of said motor-pump means and to saidaccumulator for controlling fluid flow therebetween; (g) second valvemeans connected to the outlet of said motor-pump means and to saidaccumulator for controlling fluid flow therebetween; (h) third valvemeans connected to the inlet of said motor-pump means and to saidreservoir for controlling fluid flow therebetween; (i) fourth valvemeans connected to the outlet of said motor-pump means and to saidreservoir for controlling fluid flow therebetween; and (j) startingcontrol means for selectively operating at least said first and fourthvalve means to permit fluid to flow either from said accumulator throughsaid motor-pump means to said reservoir whereby said motor-pump meansoperates as a motor to drive said engine, or from said reservoir throughsaid motor-pump means to said accumulator whereby said motor-pump meansoperates as a pump driven by said engine to pressurize said accumulator.7. The starting system of claim 6 wherein said first and fourth valvemeans each comprise solenoid-operated valves, and said starting systemfurther comprises electrical circuit means for operating saidsolenoid-operated valves.
 8. In a wheeled vehicle having an engine fordriving the vehicle and a system for selectively storing energy normallylost in braking the vehicle and using said energy to drive the vehicle,a drive transmission and engine starting system comprising:(a) anaccumulator for storing pressurized fluid; (b) a reservoir for storingfluid; (c) first hydraulic pump means mechanically coupled to the wheelsof said vehicle for being driven by said wheels, said pump means havingan inlet and an outlet; (d) first control means for selectivelyhydraulically connecting the inlet of said first pump means to saidreservoir and the outlet of said first pump means to said accumulatorfor pumping hydraulic fluid from said reservoir into said accumulatorfor storage therein under pressure in response to the driving of saidpump means by said wheels to brake said vehicle; (e) first hydraulicmotor means mechanically coupled to the wheels of said vehicle fordriving said wheels, said motor means having an inlet and an outlet; (f)second control means for selectively connecting the inlet of said motormeans to said accumulator for receiving hydraulic fluid under pressuretherefrom and the outlet of said motor means to said reservoir to drivesaid wheels; (g) second hydraulic pump means mechanically coupled tosaid engine for being driven by said engine, said second pump meanshaving an inlet and an outlet, the inlet of said second pump means beingconnected to said reservoir and the outlet of said second pump meansbeing connected to said accumulator for pumping fluid from saidreservoir into said accumulator for storage therein under pressure inresponse to the driving of said second pump means by said engine; (h)pressure responsive means connected to said accumulator and to saidengine for stopping said engine when the pressure in said accumulatorexceeds a predetermined maximum; and (i) pressure responsive means,connected to said accumulator and to said engine, for starting saidengine in response to a drop in the pressure in said accumulator below apredetermined minimum.
 9. The drive transmission and engine startingsystem of claim 8 further comprising second hydraulic motor means fordriving said engine, said second motor means having an inlet and anoutlet, and third control means for selectively connecting the inlet ofsaid second motor means to said accumulator and the outlet of saidsecond motor means to said reservoir to drive said engine for starting,while preventing the exertion of back pressure from said accumulator onsaid outlet of said second pump means, said pressure responsive meansfor starting said engine in response to a drop in the pressure n saidaccumulator below a predetermined minimum being connected to said thirdcontrol means for actuating said third control means to start saidengine.
 10. The drive transmission and engine starting system of claim 9further comprising starter cut off means connected to said engine and tosaid third control means for stopping the flow of hydraulic fluid fromsaid accumulator to said second motor means when said engine has reacheda predetermined state.
 11. In a wheeled vehicle having an engine fordriving the vehicle, a starting system for selectively storing energynormally lost in braking the vehicle and releasing the stored energy tostart the engine, said starting system comprising:(a) an accumulator forstoring pressurized fluid; (b) a reservoir for storing fluid; (c) fixeddisplacement hydraulic pump means mechanically coupled to the wheels ofsaid vehicle for being driven by said wheels, said pump means having aninlet and an outlet; (d) first control means for selectivelyhydraulically connecting the inlet of said pump means to said reservoirand the outlet of said pump means to said accumulator for pumpinghydraulic fluid from said reservoir into said accumulator for storagetherein under pressure in response to the driving of said pump means bysaid wheels to brake said vehicle; (e) fixed displacement hydraulicmotor means mechanically coupled to said engine for driving and therebystarting said engine, said motor means having an inlet and an outlet;and (f) second control means for selectively hydraulically connectingthe inlet of said motor means to said accumulator for receiving saidhydraulic fluid from said accumulator and the outlet of said motor meansto said reservoir to drive said engine for starting.
 12. The startingsystem of claim 11 further comprising starter cut off means connected tosaid motor means and to said second control means for stopping the flowof hydraulic fluid from said accumulator to said motor means when saidengine has reached a predetermined state.
 13. The starting system ofclaim 11 wherein said first control means comprises a firstdirection-control valve connected to said accumulator and to said inletof said pump means, a second direction-control valve connected to saidoutlet of said pump means and to said reservoir, a thirddirection-control valve connected to said reservoir and to said inlet ofsaid pump means, a fourth direction-control valve connected to saidoutlet of said pump means and to said accumulator, and direction-controlmeans connected to said first, second, third and fourthdirection-control valves for selectively actuating them.
 14. Thestarting system of claim 13 wherein said first, second, third and fourthdirection-control valves are each solenoid-operated and saiddirection-control means includes anelectrical circuit for actuating saiddirection control valves.
 15. The starting system of claim 14 furthercomprising a check valve connected to said outlet of said pump means andto said accumulator to permit fluid to flow from said pump means throughsaid check valve to said accumulator but to prevent fluid flow throughsaid check valve in the opposite direction.